【摘要】 在Na OH存在下,以溴乙醇为羟乙基化试剂对壳聚糖进行了改性,得到羟乙基壳聚糖(HECTS);用元素分析法(EA)确定了产物的羟乙基取代度(DS),并以产物的取代度为基准,用四因素三水平正交实验优化了反应的条件;同时,用FT-IR和~1H NMR表征了产物结构,超声辅助直接溶解法评价了产物的水溶性。结果表明,壳聚糖经碱化处理后再用溴乙醇改性,生成的产物为N,O-羟乙基壳聚糖(N,O-HECTS),羟乙基取代度为82.42%及其以上的N,O-HECTS在中性条件就具有较好的水溶性;当n溴乙醇/n壳聚糖单元=5.0,nNaOH/n壳聚糖单元=10.0,反应温度为50.0℃和反应时间为36.0h时,N,O-HECTS的羟乙基取代度可达112.39%。更多还原

【Abstract】 Chitosan was modified with bromoethanol as hydroxylation agent in the presence of Na OH and transformed into hydroxyethylated chitosan( HECTS). The substitution degree( DS) of hydroxyethyl of HECTS was determinated using elemental analysis(EA),and the reaction condition for preparing water soluble HECTS was optimized using four factors and three level orthogonal experiment.The structure of derivative of chitosan was characterized by FT-IR and1 H NMR,and the water solubility was evaluated using direct dissolution method with assistance of ultrasound.Experimental results indicated the product,which resulted from the modification of chitosan with bromoethanol as hydroxylation agent in the presence of Na OH,was N,O-hydroxyethylated chitosan( N,OHECTS),and the N,O-HECTS with DS above 82. 42% could behave excellent water solubility. When the nBromoethanol/nCTS unit= 5. 0,nNa OH/nCTS unit= 10. 0,reaction temperature was 50. 0℃ and reaction time was 36. 0 h,the substitution degree of hydroxyethyl of N,OHECTS could up to 112. 39%.更多还原